Electrode for discharge tubes



ELECTRODE FOR DISCHARGE TUBES Filed May 11, 1926 Patented Aug. 14, 1928.

" UNITED STATES PATENT oar-Ice.

GILLES HOLST, OI EINDHOVEN, NETHERLANDS, ASSIGNOR TO N. V. PHHIIIB' Application filed Kay 11, 1886, Serial No. 108,846, and in the Retherlandtl'nne 8,

This invention is concerned with improved electrodes for discharge tubes consisting of a continuous conductor bent helically or in a zigzag line.

Frequently drawbacks have been experienced when using this kind of electrodes,

their deprivation of occluded gases being beset with diflicult-i'es. In order to obviate the said disadvantage it has already been suggested to connect the two ends of a helical electrode to leading-in wires and to lead a current through the electrode while the discharge tube is being deprived of occluded gases. However, when using these electrodes there is the risk that during their calcination which has to be eifected at a very high temperature the sag, which prevents the correct mutual istance of the electrodes in the discharge tube from being maintained.

It has also been already ,su gested to secure the turns of the helical e ectrode to a rod of insulating material. This presents however the disadvantage that while the helical conductor is being heated the insulating material cannot be heated to a satisfactory extent so that it cannot be deprived of occluded gases and consequently evolves contaminating substances duringlthe use of the electrode in the discharge tube. Moreover, the a plication of the insulating material in the irect proximity of the electrodes causes static discharges which likewise entails difficulty during the use. The invention obviates the said disadvantages,

the small supporting rod of the conductor bent helically or in a zigzag line consisting of material having a substantially higher specific resistance than the material of the bent conductor. This enables a current to be led during the deprivation of the discharge tube of gases both through the bent conductor constituting the electrode proper and through the small supporting rod so as to deprive the two elements simultaneousl of occluded gases. By im art-mg to the ent conductor a materially ower specific resistance than to'th'e supporting rod it is ensured that a large part of the current supplied is led through the said conductor. Moreover a poor heat conduction is nearly always incidental to a high specific resist ance so that the Joule-heat stored in the supporting rod during the deprivation of The invention will bemore clearly understood by reference to the accompanying drawing. In the said drawin a threeelectrode tube havin a helical grid electrode is shown by way example. In the said drawing 1 is a stem tube which ends in. a pinch 2 in which the various supports and leading-1n w1res are sealed. The supporting wires 3 and 4 serve to support the anode 5 wh1ch has a cylindrical shape in the construction illustrated. The support 4 is-connected to a leading-in ,wire 6. Further supporting wires 7 and 8 are arranged to support a helical grid electrode 11. The support ng wires 7 and 8 are connected to leadmg-m wires 9 and 10 respectivel which renders it possible to heat the grid galvanlcally during the deprivation of gases. The helical conductor 11 preferably consists of nickel or any other material bein a good conductor of electricity and hem also readily deprived of occluded gases. e successive turns of the helical conductor 11 are secured to a small supporting rod 12 of constantin or other metal conductor of heat and has sistance. The attachment of the turns to the supporting rod is preferably 1} effected by welding. An incandescent cathode 13 in the form of a stretched wire is secured to two supporting wires 14 and 15, which latter are connected toleading in wires 16 and 17 It is obvious that the invention can be applied not only to three-electrode tubes but also to discharge tubes having more than three electrodes, in which the controllin grid as well as the auxiliary grid or gri may be manufactured in accordance with the which is a poor a hlgh specific reinvention. The invention can also be applied to electrodes which are not helical as in the construction illustrated but consist of a conductor in a zigzag line located in a plane. Moreover the invention can be aplied to anodes consisting of a continuous ent conductor.

What I claim is 1. In a discharge tube, electrode supports, a lead-in wire connected to each support, an electrode of such a form that it is longer than the distance between its supports, and a rod for supporting said electrode to prevent its sag ing when heated, said rod bein an electricafconductor and having electrica connection with the electrode lea in wires. 2. In a discharge tube, electrode supports, a lead-in wire connected to each support, an electrode of such a form that it is lon er than the distance between its supports, an a rod for supporting said electrode to prevent its sagging when heated said rod being an electrical conductor and having electrical connection with the electrode lead in wires, said electrode having an electrical resistance eater than the resistance of the electrode.

3. In a discharge tube, electrode supports, a lead-in wire connected to each support, an electrode of such a form that it is longer than the distance between its sup orts, and a rod for supporting said electrode to prevent its sagging when heated, the rod being -trode to prevent its sag g w nection, a nickel electrode of such form that 85 it is longer than the distance between its supports, and a rod for supportin said elec- Iien heated, said rod being an electrica conductor having a specific resistance of about 50 microhms 40 per cubic centimeter.

5. In a discharge tube, a pair of electrode supports, each sup ort having a lead-in connection, a nickel e ectrode of such form that it is longer than the distance between its supports, and a rod positioned beneath the electrode such that portions of the electrode rest upon the rod and are sup orted thereby to prevent sag ing of the e ectrode when heated, said rod ing an electrical conductor having a specific resistance of about 50 microhms per cubic centimeter.

In testimon whereof I afiix my signature, at the city 0 Eindhoven, this 23rd day of April, A. D. 1926.

GILLES HOLST. 

